diff --git a/README.md b/README.md
index ce3d857..22f0676 100644
--- a/README.md
+++ b/README.md
@@ -143,6 +143,7 @@ P.S: All these commands are tested on `git version 2.7.4 (Apple Git-66)`.
 * [Show all the git-notes](#show-all-the-git-notes)
 * [Apply commit from another repository](#apply-commit-from-another-repository)
 * [Specific fetch reference](#specific-fetch-reference)
+* [Find common ancestor of two branches](#find-common-ancestor-of-two-branches)
 
 <!-- Don’t remove or change the comment below – that can break automatic updates. More info at <http://npm.im/doxie.inject>. -->
 <!-- @doxie.inject end toc -->
@@ -973,5 +974,10 @@ git --git-dir=<source-dir>/.git format-patch -k -1 --stdout <SHA1> | git am -3 -
 git fetch origin master:refs/remotes/origin/mymaster
 ```
 
+## Find common ancestor of two branches
+```sh
+diff -u <(git rev-list --first-parent BranchA) <(git rev-list --first-parent BranchB) | sed -ne 's/^ //p' | head -1
+```
+
 <!-- Don’t remove or change the comment below – that can break automatic updates. More info at <http://npm.im/doxie.inject>. -->
 <!-- @doxie.inject end -->
diff --git a/tips.json b/tips.json
index 4bc19e9..c4cd799 100644
--- a/tips.json
+++ b/tips.json
@@ -418,4 +418,7 @@
 },{
     "title": "Specific fetch reference",
     "tip": "git fetch origin master:refs/remotes/origin/mymaster"
+}, {
+    "title": "Find common ancestor of two branches",
+    "tip": "diff -u <(git rev-list --first-parent BranchA) <(git rev-list --first-parent BranchB) | sed -ne 's/^ //p' | head -1"
 }]